1. Field of the Invention
The present invention relates generally to dental implants. More particularly, the invention concerns a dental implant which includes a tubular body portion that can be positively secured within a bore in a jaw bone by an expander mechanism, the tubular member being threaded so that a selected prosthetic component can be threadably connected to the tubular body portion immediately following securement of the tubular body to the bone.
2. Discussion of the Invention
Introduction
Dental implants of the character receivable within a bore provided in the jaw bone are old in the art. Typically such implants comprise an apertured body portion which is emplaced within a bore drilled in the bone. The body portion is designed so that during a period of about four to six months after its emplacement within the bore, bone tissue will grow into the apertures so as to secure the body portion of the implant in place within the bone bore. Following this four to six month period, an artificial tooth or other prosthetic component is secured to the body portion. This procedure is undesirable in several respects. In the first place, the procedure is protracted and requires multiple visits to the oral surgeon. Secondly, during the extended period of time required for the bone tissue to grow into and around the implant, the patient is left with an uncomfortable and unsightly cavity where the prosthetic component, such as an artificial tooth will eventually go. Additionally, this procedure does not always provide adequate anchoring of the implant to the jaw bone so that in time the implant can loosen.
In order to overcome the drawbacks of the standard procedure described in the preceding paragraph, several types of implants using mechanical locking means for securing the implant in place within the bore in the jaw bone have been suggested. Exemplary of such devices is the device described in U.S. Pat. No. No. 3,708,883 issued to Flander.
The Flander device comprises an implant which has an elongated tubular body provided with an outer anchoring portion which includes spreadable portions having projections adapted to be pressed into the bone. These portions are mechanically spread apart by an elongated spreader screw which extends through the tubular body. A nut mounted on the outer end of the tubular body is threaded onto the spreader screw to pull it outwardly causing the spreadable anchor portions to spread a part from each other and to press the projections formed thereon into the bone. The artificial tooth is then bonded to the nut and to a portion of the spreader screw.
The implant of the present invention also makes use of mechanical securement means, but unlike the Flander device, the device includes means by which selected dental prosthetics of standard design can be threadably interconnected. In this way, angular corrections of the prosethetic, such as an artificial tooth, can readily be made. Further, in one form of the device of the invention, the implant is positively secured within the bore in the bone by two separate, but cooperating securement mechanisms. The first securement mechanism comprises self-tapping, external threads provided on the tubular body of the device which are threaded into the bone by rotating the device in a first direction. The second, cooperating securement mechanism comprises a plurality of bone penetrating anchor blades formed on the skirt portion of the tubular body which are moved into a bone engagement position only after the implant has been securely threaded into the bone. In this embodiment of the invention, the anchor blades are moved into the bone engagement configuration by rotating a threaded expander member also in a first direction. However, because the threads on the expander member are opposite to the threads on the tubular body, rotational forces exerted on the expander member continuously urges the implant in a thightening direction. In other words, as the anchor blades are urged outwardly, the implant is continuously urged into threaded engagement with the bone. This novel, double locking approach permits the selected prosthetic component to be connected to the implant immediately without the patient having to return to the oral surgeon a second time.
In an alternate form of the invention, the tubular member is provided with means for locking it against rotation as the anchor blades are cammed outwardly into the bone. In this form of the invention, means are also provided for threadably connecting a wide variety of dental prosthetics to the implant immediately after the implant is secured to the bone.